Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
[0001] Multifunctional Primers
BACKGROUND
100021 This invention relates generally to a multifunctional primer for
composite building
materials, such as fiber cement building materials. In addition, it relates to
an improved primer
that functions as both a sealer and a primer.
[0003] Production of a composite building materials often requires that the
surface of the
material be modified (e.g., smoother, rougher, textured). For example,
building products may
be reduced in size by cutting (e.g., by saw or water jet), sanding, punching,
shearing. Such
modifications may not only change the appearance of the surface, they may also
leave the
surface burnished and/or with particulates and dust. Unfortunately, such
surfaces are very
difficult to coat with coating materials (e.g., sealer, primer, paint, stain).
This is particularly
true for cementitious materials, such as fiber cement. Dusty, burnished and/or
smooth fiber
cement surfaces are especially problematic and adhesion of a coating to such
surfaces is
difficult to achieve. In fact, the surface characteristics are often so
different after such
modifications that there is no adhesion of a first coating material to the
building material (e.g.,
sealer to substrate) and/or no adhesion between a second coating and the first
coating (e.g.,
topcoat to sealer or topcoat to primer).
[0004] When a sealer and a primer are desired for a building material, the
application of
separate coatings can prove complicated and costly. A typical coating process
requires multiple
heating steps, devices of cleaning, coating, application, heating, drying,
curing and packaging,
all of which reduce efficiency of work and increase usage of manpower as well
as equipment.
There are often compatibility issues between the different coating layers and
between the
coating and the substrate that must be attended to. In addition, when more
than one type of
coating is required, durability and performance characteristics of each
coating must be properly
assessed.
SUMMARY
[0004a] In one aspect of the present invention, there is provided a
multifunctional primer
formulation for a composite building material wherein the formulation includes
an emulsion
with a binder selected from the group consisting of an acrylic latex and
silicate binder, an
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acrylic latex and urethane binder and combinations thereof, wherein the binder
imparts
multifunctional action to the primer, wherein the formulation has improved
adhesion to a
composite building material as compared with primer absent the binder, and
wherein the
critical pigment volume concentration is less than about 70%.
[0004b] In one aspect of the present invention, there is provided a
multifunctional primer
formulation for the improved adhesion of a topcoat to a composite building
material, wherein
the multifunctional primer formulation includes a binder selected from the
group consisting of
an acrylic latex and silicate binder, an acrylic latex and urethane binder and
combinations
thereof, wherein the binder imparts multifunctional action as a primer and a
sealer, and wherein
the critical pigment volume concentration is less than about 70%.
[0004c] In one aspect of the present invention, there is provided a
multifunctional primer
formulation for a composite fibre cement building material wherein the
formulation includes an
emulsion with an acrylic latex and silicate binder, wherein the mass ratio of
silicate to acrylic
latex is between 0.75 and 1.5 whereby the binder imparts multifunctional
action to the primer
as a primer and a sealer and wherein the formulation has improved adhesion of
a topcoat to a
composite fibre cement building material as compared with a primer absent the
binder.
[0004d] In one aspect of the present invention, there is provided use of a
multifunctional
primer formulation, wherein the multifunctional primer formulation includes an
emulsion with
a binder imparting multifunctional action as a primer and a sealer for the
improved adhesion of
a topcoat to a composite fibre cement building material as compared to a
primer absent a
binder, wherein the binder comprises an acrylic latex and silicate binder,
wherein the mass ratio
of silicate to acrylic latex is between 0.75 and 1.5.
[0005] Described herein are multifunctional primers for a composite
building material,
such as a cementitious material, gypsum, or other inorganic composite
materials, that overcome
inadequacies described above. The multifunctional primer may be provided as a
sealer and a
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primer and offers improved features for superior adhesion to composite
building materials,
such as saw cut or sanded surfaces..
[00061 A multifunctional primer described herein includes a self-sealing
primer. The binder
included in the primer may be an acrylic silicate binder, an acrylic. urethane
binder, an acrylic
.sifoxane binder or any combination thereof Accordingly, the multifunctional
primer'
formulation for a composite building material as described herein includes an
emulsion with an
acrylic silicate binder or an acrylic urethane binder or an acrylic. siloxane
binder that imparts a
multifunctional action to the substrate and the topcoat applied thereafter.
!OW] Such a formulation with, an acrylic silicate binder may comprise a
dispersant as a
.solution of 4 sodium salt of an aerylate copolymer, a surfactant as a
nonionic surfactant,
and/or a polysilicone defbamer. in one form, the acrylic is an acrylic latex.
The acrylic-
silicate binder ratio is typically between. about. 0.5 and about 1,.5. The
formulation further
comprises a pigment, which may be in the. form of titanium oxide or other
suitable pigments.
When the formulation comprises a Rel.; particles are typically less than 10
micron. The.
multifunctional action includes functioning as .a primer and a sealer and the
multifunctional
action is maintained with addition of a topcoat.
[0008] With an acrylic urethane binder, a formulation may comprise a
dispersant as a
solution of a sodium salt of an acrylate copolymer, a surfactant as a solution
of
alkylammonium salt of a polyffinctional polymer with anionic or non-ionic
character and/or a
non-silicon defoamer. The acrylic may be a hydroxyl-ffinctional acrylic
copolymer. The.
formulation may further comprise a polyisocyanate cross-linker, a pigment
such. as titaninm.
oxide, a filler with particles less than 1 micron, and/or a solvent of
ethylene glycol .monobutyl
ether, The multifunctionai action includes functioning as a primer and .a
sealer and the
multifunctional action is maintained with addition of a topcoat.
10009] Those skilled in the art will further appreciate the above-noted
features and
advantages of the invention together with other important aspects thereof
upon. reading the
detailed description that follows and in conjunction with the drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
[00101 For more complete understanding of the features and advantages of the
inventions
described herein, reference is now made to a description of the invention
along with
accompanying figures, wherein:
100111 FIG.. 1 illustrates wet adhesion as a function of pigment volume
concentration, in a
multifunctional primer formulation described herein;
100121 FIG. 2. illustrates wet adhesion as a function of the weight ratio
between silicate
binder and acrylic binder in a :multifunctional primer formulation described
herein;
[00131 .FIG, 3 depicts a representative bar graph showing dry adhesion of a
multifunctional
primer formulation. described herein when applied at varying thicknesses on
sanded faces of a
composite building material;
100141 FIG. 4 depicts a representative bar graph showing dry adhesion of a
multifunctional.
primer formulation described herein when applied at varying thicknesses on saw
cut edges of a.
composite building material;
[00151 FIG. 5 depicts a representative bar graph showing wet adhesion of a
multifunctional
primer formulation described. herein with a topcoat on sanded faces of a
composite building
material when the multifunctional primer is applied at different thicknesses;
and
100.161 FIG. 6 depicts a representative bar graph showing wet adhesion of a
multifunctional.
primer formulation described herein with a topcoat on sanded faces of a
composite building
material when the multifunctional primer is applied at different thicknesses.
DETAILED DESCRIPTION
[00171 Although making and using various embodiments are discussed in detail
below, it.
should be appreciated that the description provides many inventive concepts
that may be
embodied in a wide variety of contexts. The specific aspects and embodiments
discussed
herein are merely illustrative of ways to make and use the invention, and do
not limit the scope
of the invention.
[00181 .Described herein, in. one or more embodiments, are primer
formulations. The primer
has multifunctional capabilities: and is self-sealing in which it acts as a
sealer and a primer.
The term "sealer" is used herein in its general meaning of a substance
(coating) applied to a
substrate, typically as a basecoat for paints, stains, varnish, as examples.
The primer
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formulation is designed for use on building material substrates, preferably
composite building
materials, including fiber cement substrates having saw cut and sanded
surfaces.
00191 Formulations for a multifunctional primer as described herein are
identified in
TABLE 1. A typical formulation includes at least one carrier, solvent,
surfactant, dispersant,
thickener, defoamer, pigment, filler, and resin binder. In one or more
embodiments, the resin
binder is a silicate acrylic latex, silicate acrylic Copolymer, silicate
styrenated acrylic, urethane
acrylic latex or any combination thereof. Multifunctional primer formulations
may include a
general range as presented in TABLE 1.
rTABLE 1. Formulations of one or more embodiments
Acceptable range A preferred range
Component
( I/VAV) NWT)
carrier 0-50 10-35
surfactant. 0-2 0.1-0,6
dispersant 0-2 0.1-1.5
resin binder 10-80 30-60
thickener 0-1 01-0.3
filler 0-30 5-20
defoamer 0-1 01-04
solvent 0-5 0-3
=
pigment 5-30 10-20
[00201 The binder used typically with TABLE 1 includes an acrylic latex and
silicate binder
and/or an acrylic-urethane binder, in some embodiments, the resin binder is
silicate acrylic
latex. In such a formulation, the silicate binder may be sodium silicate
.and/or potassium
silicate. The surfactant is suitably a non-ionic surfactant, often, when
desired. octyl phenol
ethoxylate. The dispersant typically acts as a stabilizer and includes a.
solution of a.sodium salt
of an acrylate copolymer. The thickener is typically a urethane-based rheology
modifier. The
filler is typically a fine, calcium carbonate having particles less than 10
microns in size: The
defoamer is typically an acetylenie-modified polysiloxane-based defoamer or a
parraffmic
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defoamer. Often, when desired, both types of defoamers arc provided to. the
formulation. A
pigments includes those typically used with primer formulations. A suitable
pigment is.
titanium dioxide.
00211 In additional embodiments, the resin is an acrylic-urethane binder. In
such
.formulation, the surfactant is suitably a solution of an alkylammonium salt
of a polyfunctional
polymer with anionic/non-ionic character. The dispersant typically acts as a
stabilizer and
includes a solution of a sodium salt of an acrylate copolymer. The cross-
linker is typically a
polyisocyanate cross-linker (with or without a blocker). The tiller is
typically talc having
particles about 1 to 10 microns in size. The defoamer is typically a non-
silicone defoamer,
The solvent is generally ethylene glycol. Or ethylene glycol monobutyl ether.
A pigment is a
typical pigment suitable for primer tbrmulations, such. as titanium dioxide in
a quantity and,
with the addition of other ingredients., help prevent undue settling..
[00221 .Additional features of multifunctional primers described herein are
shown in TABLE
2.
TABLE 2.
Solids.
NNW (%). T41 V V (yo.) T PC .(%) CPVC
(%)
' ___________________________________________________
Range Pref. Range Pref Range I Pref. Range Pref Range
Pref.
.. . .
<15 <12 40-70
40-60 20-60 25--45 20-50 30-40 40-70 <60
Pref. = .an embodiment; .NVM = solids co-mein by mass; NVV = solids content by
volume;
PVC = pigment volume concentration; CPVC = critical pigment. volume
concentration.
[00231 An example of a formulation having an acrylic-silicate 'binder is
provided in TABLE.
3. Resin binder A is in the -form of, for example, an. acrylic binder: Resin
binder B is in the
form of, for example, a silicate binder. Such a formulation as shown in TABLE
3 provides an
NVIM of less than 44%, an NVV of less than 27%, PVC of about 40% and CPVC of
about
57%, when prepared as a formulation of 'about 101 I Iblgal,
TABLE 3.
Component Amount
(lb.)
-water >300
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surfactant. <2.0
dispersant/stabilizer >2:0
resin binder A. 200-29.0
resin binder B 200-290
cross-linker 50-1:00
filler 1.20-180
defoamer >1.0
Thickener
pigment 10022.00
100241 An example of a formulation having an acrylic-urethane binder is
provided in.
TABLE 4. Such a fomulation as shown in TABLE 4 provides an NVM of less than
60%, an
NVV of less than 45%, PVC of about. 30% and CPVC of about 52%, when prepared
as a
formulation of about 11-12 lb/gal.
TABLE 4.
Component .Amount
(lb.)
water 25-60
surfactant <1.0
dispersant/stabilizer >5.0
resin binder 70-1.00
cross-linker 50-100
filler /5-60
defoamer >2.0
pigment
50-100
100251 In a further example of a formulation comprising an acrylic-urethane
binder, the
formulation includes water as the carrier at about 50 lb/gal, a surfactant at
about 1,0 lb/gal, a
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dispersant that is about 4.8 lb/gal, a solvent at 7.0 lb/gal, at least two
titianium oxide
pigments, one at about 30 lb/gal and the other at about 40 lb/gal, .a filler
at about 50 lb/gal, an
acrylic binder that is at about 90 lblgal and an isocyanate binder that is at
about 75 lb/gal.
100261 An example of pigment volume concentration as a function of wet
adhesion is
depicted hi FIG. 1. With HQ. 1, wet adhesion was performed on outer saw cut
edges of
composite building material samples surfaced with a coating of a.
multifunctional primer
tbrmulation described herein and a topcoat, which was a water-based acrylic
topcoat. The
multifunctional primer included an acrylic-silicate binder, which was applied
at a thickness of
about 0:9 milL the topcoat was applied at a thickness of about 1.6 mils. FIG.
1 illustrates that
fOr such a formulation having a pigment volume concentration of between about
30% and
.44% very good wet adhesion was achieved when applied to the composite
building material
which included a water-based acrylic topcoat.
[09271 For wet adhesion, samples included cementitious composite building
specimens
provided as sanded and sawcut boards having the following approximate
dimensions: 3.5 inch
x 12 inch x l inch.. Applied to edges of each specimen (that has been sanded
and sawcut), at
room temperature and under initial moisture conditions of 0%-50%, was about
0.9 mil DFT
of a multifunctional primer described herein in the absence of a sealer. The
multifunctional
primer was cured at an elevated temperature (e.g., by baking to reach a
surface temperature of
about 140 to 190 degrees Fahrenheit) and allowed to cool. This was followed by
application
of a about 1.5 mil DFT of an acylic latex topcoat that was cured at a similar
elevated
temperature and allowed to cool. Specimens Were then soaked for about 24 hours
in water.
Paper towels were used to remove water from the surface of each specimen after
soaking,
00281 Wet adhesion were performed on composite building material specimens
coated as
described above using 3M1'm Scotch. 250 tape (St. Paul, Minnesota). Tape was
1 inch wide.
Following application of the tape to the edge of the specimen, the tape was
rolled with a 10
pound roller and then. removed .quieky. Wet adhesions on at least 10 specimens
were
performed for each of FIG. 1 and Ha 2.
100291 For FIG. 1, the silicate binder-to-acrylie binder ratio. was about
(Ibilb). An
illustration of the silicate binder-to-a.cylic binder mass ratio is depicted
in FIG. 2, in which
specimens were prepared as described previously. For FIG. 2, wet adhesion was
performed
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on saw cut edges of composite building material samples surfaced. with a
coating of a
multifunctional printer formulation described herein and a topcoat of 100%
acrylic latex. The.
multifunctional primer was applied at a thickness of about 0.9 mil and the
topcoat was applied
at a thickness of about 1.5 mils. FIG., 2 also shows that a suitable weight
ratio is between.
.about 0.7.5 and about 1.5 of a silicate binder to an acrylic binder.
[00301 FIG. 3 illustrates the degree of chy adhesion,: as a percentage of the
multifunctional
primer That is removed by the tape, after application of an acrylic-urethane
multifunctional
primer on sanded faces of cementitious building. composite 'Samples. The=
figure shows that
regardless of thickness of the multifunctional primer applied to the sanded
faces, the
multifunctional primer Showed very good dry adhesion with. generally less than
6,5% of the:
multifunctional primer removed by the tape. Thickness did not substantially
change the
degree of adhesion. When desired, a thicker multifunctional primer may be used
to reduce
removal to less than 2.5%. Thickness of the primer .described herein will also
help manipulate
the overall appearance of the primer on the coated article.
[00311 FIG. 4 illustrates the degree of dry adhesion, as a percentage of the
multifunctional
primer that is removed by the tape, after application of an acrylic-urethane
multifunctional
primer to saw cut edges (sides) of cementitious building composite samples. As
with FIG.
regardless of the thickness of the multifunctional primer applied on the
edges, the
multifunctional primer showed very good dry adhesion with generally less than
7.5% of the
multifunctional primer removed by the tape. The thickness did not
substantially change the
degree of adhesion. Again, thickness of the multifunctional primer appears to
effect degree of
adhesion; a thicker multifunctional primer may be used to reduce removal of
the primer from.
saw cut sides of a composite building material. Thickness of the primer
described herein will
also help manipulate the overall appearance on the coated article.
00321 FIG. 5 illustrates the degree of wet adhesion of an acrylic-urethane
multifunctional
primer, as a percentage of the coating that is removed by the tape, when
measured for sanded
faces of a cementitious building composite to which was applied a primer and
an acrylic latex
topcoat: As with FIGS. I and 2, FIG. 3 indicate that regardless of the
thickness of the
multifunctional primer applied, the coating adheres very well under wet
conditions, with less
than 8.0% .removal by the tape. The thickness did not substantially change the
degree of
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adhesion. When desired, a thicker multifunctional primer may be applied to
reduce removal to
less than 2.5%.
100331 FIG. 6 illustrates the degree of wet adhesion of an acrylic-urethane
.multifunctional
primer, as a percentage of the coating that. is removed by the tape., when
measured for sawcut
edges of a cementitious building composite to which a primer and an acrylic
topcoat were
applied thereon.. The DFT of the multifun.ctional primer was found to
positively affect
adhesion when applied to the edges of a. composite building material. A
coating thickness of
0.75 mil or higher provided less than 11.3% removal of the coating (topcoat)
under wet
conditions.
100341 Sp ens used herein were provided to represent a composite building.
material that
is typically a porous material. comprising one. or more different materials,,
such as a gypsum
composite, cement composite, geopolymer composite or other composites having
an
inorganic binder. .The surface of the material may be sanded, saw-cut,
punched, water jet cut,
sheared, machined, polished, extruded, molded or otherwise formed into any
desired size and
shape by various processes known in the art: The composite building materials
may be fully
cured, partially cured or in the. uncured "green" state. Composite building
materials may
further include gypsum board, fiber cement board, fiber cement board
reinforced by a mesh or
continuous fibers, gypsum board reinforced by short fibers, a mesh or
continuous fibers,
inorganic bonded wood .and fiber composite. materials, geopoiymer bonded wood.
and fiber
boards,. concrete roofing. tile material, and fiber-plastic composite
material. Desireable fibers
include various forms of cellulose fibers, such as treated or untreated,
bleached or unbleached
.Kraft pulp. ID addition, other forms of fibers may be used. Suitable.
examples are those from
ceramic, .glass, mineral wool, steel, and synthetic polymers (e.g.,
polyamides, polyester,
polypropylene, polymethylpentene, polyacrylonitrile, polyacrylamide, viscose,
nylon, PVC,
PV.A, rayon, glass ceramic, carbon, any mixtures thereof).
[00351 Any additional additive may be optionally incorporated into a composite
material
including but not limited to density modifiers, dispersing agents, silica
fume, geothermal silica,.
fire retardant, viscosity modifiers, thickeners, pigments, colorants.,
dispersants, foaming
agents, flocculating agents, water- proofing agents, organic density
modifiers, aluminum
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powder, kaolin, alumina trihydrate, mica, metakaolin, calcium carbonate,
wollastonite,
polymeric resin emulsions, hydrophobic agents, and mixtures thereof
100361 Embodiments of the multifunctional primer described herein provides
improved
physical and chemical .properties to the building material substrate as
compared. with current
primer formulations. The primer formulation described herein is
multifunctional and may be
applied as a sealer and primer in a single coating.
[00371 in desired implementations, a: multifunctional primer formulation as
described herein
provides very good adhesion when applied to a composite building material, The
pigment
volume concentration for the formulation as well as a resin-to- binder ratio
may be
manipulated to. provide even more of an improvement in properties when
desired.
(0038l in another embodiment, a multifunctional primer as described herein is
applied to a
dusty or polished surface Of a fiber cement substrate. The multifunctional
primer improves
adhesion. between the substrate. and the primer. The multifunctional primer
also improves
adhesion of a topcoat, such as paint, varnish, stain.
p3039] A multifunctional primer formulation as described herein also provides
a composite
building material with in-proved adhesion to interior or exterior coatings,
Importantly, the
formulation as designed will offer superior durability and performance as
compared with.
conventional products. By way of examples are those provided below, which are.
representative and non-limiting.
i00401 Example. 1. In a 1000 mt, stainless steel container, 350 g distilled
water, 1.6 g
Triton X. surfactant (registered trademark. of Rohm & acrig Company,
Philadelphia,
PA), 1.6 g BYK 155 dispersant (registered trademark of Byk-Cera, Germany),
1.6 g
Acrysor Itrvl-SW thickener (trademark of Rohm & Haas Company, Philadelphia,
PA), and
0.5 g Surfynor DF66 defoamer registered (trademark of Air Products and
Chemicals, Inc.,
Lehigh Valley, PA) were mixed at medium speed for .20 to 30 minutes until a
homogeneous
mixture was obtained.. Subsequently, a powder mixture containing 80 g h02, and
140 g
calcium carbonate was added. The mixture was then grinded in a high speed
disperser for 30
to 45 minutes until a Hegman fineness. of 5-6 was achieved. The letdown
procedure involved
slowly adding 264 g LICAR7 626 acrylic resin (trademark of Union Carbide
Corporation,
Houston, TX) while mixing a low speed for 10-15 minutes, followed by the
addition of 264 g
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Kase 1 potassium silicate resin. (registered trademark of PQ Corporation,
Valley Forge, PA)
and mixing at low Speed for another 10-15 minutes. Once completed, Ø1 g Dee.
Fe 3010A
defoamer (registered trademark of Munzing Chernie GmbH, Genriany) was added
and mixed
for 10-45 minutes. Finally, pH of the. primer mixture was measured and
adjusted to 8-9, and
the self-sealing primer was then .filtered through a 200 micron filter paper.
E0041.1 Once prepared, the multifunctional primer of Example 1 was applied,
using a brush
(e.g., foam brush; however, other methods of application known to one of
ordinary skill may
be used). One or a number of surfaces may be coated with a multifunctional
primer. For
example, a raw fiber cement substrate may have a top sanded face and .four saw
cut edges of
raw. .Some of all .of the surfaces of the substrate may be coated. The amount
of wet primer
applied was controlled with. an analytical. balance to achieve the target dry
film thicknesses on
both face and edges. The typical size of fiber cement samples was 3,5 inch x
12 inch x 1 inch
with the initial moisture content of 5 to 50% by weight and the initial board
temperature of
50" to 180" F. The coated fiber cement samples (having wet primer on top face
and edges)
were then cured in a lab-size conveyor oven, with a 'temperature set point of
450 F and an
adjustable belt speed, to achieve a board surface temperature of 160' to 190
F at the oven
exit.
00421 Primed samples were kit to further cure at room conditions for .at least
24 hours
before additional, analysis were performed.
[0043] When samples were further coated with a topcoat, primed boards, once
exiting the
oven, were allowed to cool down to about 90" to 140' F before application of
the topcoat.
The topcoat was a water-based, exterior grade, 100% acrylic latex. The amount
of topcoat
(applied by brush) was controlled with an analytical balance to achieve 1.5-
2..5 mils DFT on its
face and edges. Subsequently, the topc.oated samples were cured in The
conveyor oven to
achieve a board surface temperature of 160' to 190" F at the oven exit. All
coated samples
were allowed to further cure at room conditions for at least 24 hours before
additional
analysis were performed.
.0044] Example 2. In a 500 ml stainless steel container, 50 g distilled water,
7 g ethylene
glycol moneoutyl ether solvent, 1.0 g BYe 181 surfactant (registered trademark
of Byk-
Cera, Germany), 4.8 g BYle 155 dispersant (registered trademark of Byk-Cera,
Germany),
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and 1.0 g Surfrxe DF75 defoamer (trademark of Air Products and Chemicals,
Inc., Lehigh
Valley, .PA) were mixed at medium speed for 20 to 30 minutes until a
homogeneous mixture
was obtained. Subsequently, a powder mixture containing 30 g Hitox.1) TiO2
(registered
trademark of Tor Minerals, Corpus Christi, TX), 40 g Ti-Pure R931 TiO2
(registered.
trademark of E. I. DuPont de Nemours and Company, Wilmington, DE) and 50 g
Pioneer
Talc 2620 was added. The mixture was then grinded in a high .speed disperser
for 30 to 45
minutes until a Hegman :fineness of 5-6 was achieved. The letdown procedure
involved slowly
adding 90 g Carbosee) CR717 acrylic resin (registered trademark of The
Lubrizol
Corporation; Wickliffe., OH) while mixing at low speed for 10 to 15 minutes,
followed by the
addition of 75 g Rhodocoe WT (trademark of Rhodia Inc., Cranbury, NJ) 1000 and
mixing
at low speed for another 10 to 15 minutes. Once completed, pf1 of the primer
mixture was
measured and adjusted to 8 to 9, and the primer was finally filtered through a
200-micron
filter paper.
j0045] Once prepared, the multifunctional primer of Example 2 was applied,
using one-inch
foam. brushes:. The primer was applied to the top sanded face and four saw cut
edges draw,
uncoated fiber cement samples. The amount of wet primer applied was controlled
with an
analytical balance to .achieve a target dry film thickness on the face and
edges. The typical
size of a fiber cement samples was 3.5 inch x 12 inch x 1 inch with the
initial moisture content.
of 5 to 50% by weight and the initial board temperature of 50 to 180 T. The
fiber cement
samples with wet primer OP top face and edges were then cured in a lab-size
conveyor Oven,
with a temperature set point of 450 F and at adjustable belt speed, to
achieve a board surface
temperature of 160 to 1900 .IF at the oven exit:
f0046] Primed samples were left to further cure at room conditions for at
least 24 hours
before any further analyses were performed.
[0047] Some samples were further coated with a topcoat. Here, primed boards.,
once
exiting the oven, were allowed to cool down to 90' to 140 F before
application of the
topcoat. The topcoat was a water-based, exterior grade, 100% acrylic latex.
The amount of
topcoat, brushed on was controlled with the analytical balance to achieve 1.5
to 2.5 mils OFT
on face and edges. Subsequently, the topcoated samples were cured in the
conveyor oven to
achieve a board surface temperature of 160' to 1900F at the oven exit, All
coated samples
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were 'limber cured at room conditions for at least 24 hours before any further
analysis was
performed..
[(10481 The examples and descriptions herein show multifunctional primer
formulations
described herein have improved adhesion to composite building materials.
The
multifunctional primer acts as a primer and. sealer, in part from the binder
provided in the
formulation, which may comprise an acrylic latex and silicate binder, an
acrylic siloxane
binder, an acrylic-urethane binder or combinations thereof, Such formulations
may be applied
to a suitable composite substrate surface, even one that includes particulates
or are dusty or
polished:
[00491 The .multifunctional primer formulation when provided offers improved
adhesion of a
topcoat applied to the multifunctional primer. Thus, formulations disclosed
herein when
applied to a suitable substrate, which is a generally porous composite
material, provide
excellent adhesion of a further coating, such as an interior or exterior
paint, stain, and varnish,
to the substrate, including those having manipulated, engineered, dusty and/or
burnished
surfaces. As such, the: multifunctional primer described heroin, improves the
service, life of a
paint and/or topcoat when applied to themultitlinctional primer .and is
capable of maintaining
durable contact between the composite substrate and any exterior coating
(e.g:, stain or paint)
applied thereon.
100501 An improved multifunctional primer formulation as described herein
effectively
bio4s moisture from penetrating the composite building material. The
multifunctional primer
formulation when prepared and applied to. a composite building material
provides good wet
and dry adhesion to the composite building material. Adhesion may be
manipulated by
varying the thickness of the applied muhifunctional primer formulation,
Moreover, the
multifunctional primer formulation when applied, to a composite building
material provides
good wet and dry adhesion of a topcoat (e.g.., stain or paint) when further
applied to the
composite building material.
100.51.1 Although. the foregoing description of the embodiments has shown,
described and
pointed out certain novel features of the invention, it will be understood
that various.
omissions, substitutions, and changes in the form of the detail as illustrated
as well as the uses
thereof, may be made by those skilled in the art, without departing from. the
scope of the
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WO 2009/006324 PCT/US2008/068626
invention.. Particularly, it will be appreciated that the embodiments may
manifest itself in other
shapes and configurations as appropriate for the end use of the article made
thereby,
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